If you are going right by Hume on the way out start a little later and meet in Flint hill at 11:30?
http://www.griffintavern.com/
That's what time they open. Then do a long loop after lunch. I know some interesting country gravel and paved roads in the area.
You can ride from Luray to Front Royal only using 340 for a little over three miles.
Fort Valley is always a good ride too with some cool side roads!